Purging the PGI-9 cartridges

[The Hat]

I have just received my mini scales & weighed the new OEM carts & they weigh 31.32g. In Joe's video he refills his carts to 33g which I imagine is what his new full carts weighed. Do you think this difference is in our scales? I'm wondering because I'm not sure when I refill whether to fill to 31.32g or 33g like Joe. What do you lot fill to?

Take the middle of the road Rod and fill to 32 gm.
So long as its over the OEM weight it wont bother a Wallabys foot..

 

[ThrillaMozilla]

Do you think this difference is in our scales?

Shouldn't be, but do yourself a favor and buy a 100g weight. Amazon has some cheap ones for around $5 that are amazingly good.

 

[jtoolman]

Rodbam I never did weigh my original OEM carts as they had already been partially used up, and the second set of carts where purchased empty from Procission Colors ( Mikling ) which is the set I used in my dribble refill video. When you dribble fill to the top, where the ink is pooling in the sponge, and you aspirate of blot the excess, you will have about 31-33 grams. Those bags at their max will differ in volume they can accept using a simple passive filling method as the dribble method.
The factory injects a set amount of ink probably using a rig not too different from what The Hat came up with, and very likely be a couple of ML less than what is actually possible if we simply fill till it full.
Of course this is just my humble, unscientific oppinion.
These cheap gram scales are not that accurate along their range from zero to max. give or take! Only a laboratory grade scale would be reliable.

 

[mikling]

All digital scales should go through a calibration routine...with the reference weight Thrilla has mentioned. Time to read the manual.

Interestingly the specific gravity of ink varies by color a little. So you should expect slight variances in the weight with each cartridge...you will or will not observe this depending on the accuracy and resolution of the scale.

Did the instructions not include the weight range to expect?

 

[jtoolman]

The may get calibrated using a standard weight say within the middle of their total range. But that will not guarantee that they will be accurate throughout their complete range. But it's really close enough for our use and I feel that we often become far too involved in splitting hairs.

Just fill the darn things till they show a flooded sponge, if they weigh from 31 to 33 grams, sqeeze the side, bubbles will likely come to the top, blot off excess, snap on the caps and you are done. Of course I am using ARC so resetting is automatic.

Yes, I did notice the diffrences in specific gravity in different colors and yes you are 100% correct Mike. That is very likely the cause for the varying weights between carts when all where filled to a visually FULL condition.

No biggie! In practice it all works very well. By the way, the ink monitoring has been very good even with the ARC.

 

[ThrillaMozilla]

These cheap gram scales are not that accurate along their range from zero to max. give or take! Only a laboratory grade scale would be reliable.

I checked mine against a 4-place Mettler balance (which is accurate to about 0.0002 g), and it's incredibly accurate over the whole range, within one or two numbers in the last digit. It literally could not possibly be any more accurate. It also holds its accuracy without recalibration. It cost about $13 including shipping.

If you really want to check the balance over the whole range, it's not difficult to do. First, get yourself a reference weight to calibrate the balance. For these small electronic scales this is usually an inexpensive 100 g weight. You could skip that step if you want, but it does assure you of some additional accuracy and reproducibility. My balance has held its calibration for months, but it's good to be able to check somehow.

Then you need to test the linearity. The procedure is not hard. This is the classical procedure for calibrating chemical analytical balances and weights. Get yourself some smaller weights (coins will do). Weigh them individually, and then weigh them together in various combinations. You'll want totals spanning the whole range, like 25g, 50g, 75g, etc. (The exact numbers don't matter. It could be 19, 55, etc.) Here's the key: the measured weights should equal the arithmetic sums. Remember that there will be some small roundoff errors. You can reduce the roundoff errors by using a number of small weights and getting many data points.

Overkill? Maybe. As I said, mine is incredibly accurate. But if you do this, you know there's no error.

 

[ThrillaMozilla]

Just fill the darn things till they show a flooded sponge, if they weigh from 31 to 33 grams, sqeeze the side, bubbles will likely come to the top, blot off excess, snap on the caps and you are done.

Now you're talking. Sometimes you don't even know the correct full weight, and this works. I don't have this type, but if I fill to the tippy-top, I always withdraw 1 mL or so just to guarantee that there's a vacuum.

 

[jtoolman]

Thrilla, Yes mine is pretty accurate and it better be as I paid a whopping $20 for it. What I was trying to emphasize is that we are being too concerned with making sure the filled cart is 31 - 33 depending on color. And yes I've been able to get some to weigh more than others but on the svarage it is about 31-33 grams not counting the clip.
The factory loads are always going to be quite exact but but I've experienced is that if I fill till the sponge is flooded, I get varying weights from 31 to 33 grams. So assuming that the same volume is being accewpted by each cart , the difference in weight could very well be atributed to different specific gravities of each ink. Sone being more " Dense " than other.

Since I love to print a more than refilling, it doesn't really matter.
Fill to the top, remove bubbles and blot, PRINT!!!!!

 

[mikling]

Done. KISS principle

 

[ThrillaMozilla]

If it were mine, I would fill it by weight, but stop at the Canon weight and fill it a little less than chock full--just to be on the safe side.